Large amounts of hazardous medical waste are generated by hospitals, clinics, veterinarians, undertakers, physical therapists and other sources. Sterilizing and disposing of such "red bag" waste material, as well as other forms of contaminated biological waste products, has become an increasingly expensive and annoying concern.
Several generally accepted methods of treating medical waste are presently available. These include incineration, chemical treatment and steam sterilization. However, each such technique exhibits certain shortcomings.
Incinerators are usually unsightly and expensive. Moreover, they tend to pollute the environment. Medical waste is a particular problem for incinerators because such waste typically comprises about 30%-35% plastic. When such material is burned, a variety of hazardous gases are emitted. As a result, incinerators are often subjected to burdensome governmental regulations relating to emissions, safety, zoning, and permitting. Emissions may be severely restricted, for example, to five hundred pounds of waste burned per hour. Alternatively, for handling larger amounts of waste, expensive, scrubbing may be required. All medical waste incinerators must employ afterburners, which greatly increase fuel usage. In short, the expense, inefficiency and regulation of incinerators makes their use impractical in most situations.
Sterilizing chemicals present their own set of problems. Ethylene oxide is dangerously explosive and poisonous. Formaldehyde is flammable and toxic. Chemicals also can be difficult to test and transport. And, like incinerators they are typically subjected to close monitoring and extensive government regulation.
Steam sterilization has been employed to sanitize medical equipment and red bag waste. However, conventional steam systems are usually quite inefficient for waste. Typically, such systems include a room size chamber that must be heated to a predetermined sterilizing temperature of approximately 250 degrees Fahrenheit for a predetermined time (e.g. 30 minutes). Such chambers may exhibit cool spots and experience expensive time delays during the heating up and cooling down stages. Moreover, a variety of viruses, bacteria and, in particular, bacterial spores can often survive the steam treatment because of cold spots and other problems. And, in order to prevent the cold spots due to air being present, an elaborate pumping system is required to draw air out of the chamber and replace that air with steam. Additionally, conventional steam systems are not cost efficient for treating a single bag or container of waste. Typically, the system is not operated until a large batch of waste is available. As a result, large amounts of contaminated material can be stored untreated, often for a substantial period of time.